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-   -   40hp 2 stroke carb help needed (https://www.offshoreonly.com/forums/general-q/386046-40hp-2-stroke-carb-help-needed.html)

compedgemarine 07-28-2025 08:12 AM

40hp 2 stroke carb help needed
 
took the cougar cub out yesterday and fixed a couple of the issues I had but now that it is working right it feels like it is running rich. when I look up the carb jets they show 10 different ones-.054 to .062 in .002 increments and .088 to .096 in .002 increments. how do I know what I should start with and why nothing in between those sets? I assume it has to do with elevation or maybe something else as I am not that familiar with 2 stroke outboards. any one have a book on these that explains it? engine is a 1999 Force 40hp 2 stroke.

mcollinstn 07-31-2025 08:46 AM

Carb tuning requires something more definitive than "feels like it might be rich". You need to learn how to read a spark plug and how to do a wide open plug chop.

compedgemarine 07-31-2025 05:41 PM

I get that and I have only run it once fixing other things but what confused me is the set of 5 jets listed and then a huge jump and another 5 listed. assuming that there is a chart for elevation or something that says what they wanted in it as a starting point. I know nothing about the engine as I paid $100 for it and it runs pretty nice so for the price I can play with it. the problem with doing a wide open run and cutting the engine is that you most likely will die. the boat is only 10 ft and a hand full as it is. plus you cannot cut the throttle and shut it down as the wake coming up behind you will go over the entire boat as she only has about 4 inches of freeboard at the rear. it is fun and I can run it like it is just trying to understand the strange jets offered for it.


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